The present invention generally relates to methods and apparatus for recording an information signal on a rotary recording medium, and more particularly to a method and apparatus for assembling an information signal on a rotary recording medium comprising a pre-recorded track recorded with pre-recorded information signals and an unrecorded track not recorded with information signals, in which an information signal is newly recorded on an unrecorded track turn which is a portion of the unrecorded track immediately following a pre-recorded track turn, the pre-recorded track turn being a portion of the pre-recorded track located at an end of the pre-recorded track, in such a manner that the information signal to be newly recorded on the unrecorded track turn is recorded continuously from the end of the pre-recorded information signal recorded on the pre-recorded track turn.
Conventionally, there is a recording and reproducing apparatus capable of recording and reproducing an information signal on and from a rotary recording medium such as an optical disc hereinafter referred to as a disc along a spiral track by scanning a light beam. In such an apparatus, there are instances that a user wishes to record a new information signal on a disc having an unrecorded track not yet recorded with information signals and a pre-recorded track already recorded with pre-recorded information signals in such a manner that the newly recorded information signal is recorded continuously from the pre-recorded signals without causing any interruption of recording between the pre-recorded signals recorded on the pre-recorded track and the newly recorded signal recorded on the unrecorded track. Such a recording operation will be referred to hereinafter as assembling.
In the following description, a term track turn is used in a sense to indicate a portion of the track scanned by the light beam during one revolution of the disc.
Conventionally, the assembling of new information signal on the disc is achieved by scanning an unrecorded track turn immediately following a pre-recorded track turn using a recording and reproducing device producing the light beam. The light beam repeatedly scans the unrecorded track turn while waiting for a video signal to be newly recorded to the disc, and in response to the video signal to be recorded, the operation mode of the recording and reproducing device is switched from a reproducing mode to a recording mode and the the video signal to be newly recorded is recorded on the unrecorded track turn.
In the aforementioned assembling operation, the light beam repeatedly scans the unrecorded track turn of the disc by moving repeatedly backward by one track pitch across the track at each end of the track turn during one revolution of the disc with a timing predetermined relative to the rotaion of the disc. This movement is referred to hereinafter as a jump. As the assembling starts with a position which is located at the beginning of the unrecorded track turn, the recording and reproducing device has to be jumped back to this position each time the light beam scans the end of the track turn.
Unfortunately, the operation of an actuator causing the jump of the light beam is not stable for those intervals immediately after the jump, so that some extent of unstability in the scanning of the light beam is inevitable. As a result, the conventional method of assembling the information signal on the disc has a problem that the recording is unstable particularly for those portions of the unrecorded track turn which immediately follows the pre-recorded track turn at which the assembling operation begins.